sql on delete code example

Example 1: sql delete

DELETE FROM my_table;		-- all rows
DELETE FROM my_table WHERE my_id = 12345;
DELETE FROM my_table WHERE my_id IN (SELECT id2 FROM my_table2);
COMMIT;		-- don't forget it...

Example 2: SQL DELETE

Mit DELETE werden einzelne oder mehrere Datensätze gelöscht. Mit WHERE 
werden nur bestimmte Datensätez gelöscht. 

  DELETE FROM suppliers
  WHERE 
      supplier_name = 'Microsoft';

Example 3: sql delete

Delete data from a table.
Example: Removes a user with a user_id of 674.
DELETE FROM users WHERE user_id = 674;

Example 4: what is delete in sql

DELETE -
-DML COMMAND
-Delete Rows from the table one by one
-We can use where clause with Delete to delete single row
-Delete is slower than truncate
-ROLLBACK is possible with DELETE

DROP-
-DDL COMMAND
-Delete the entire structure or schema
-We can't use where clause with drop
-Drop is slower than DELETE & TRUNCATE
-ROLLBACK IS NOT POSSIBLE WITH DROP

TRUNCATE-
-DDL COMMAND
-Truncate deletes rows at a one goal
-We can't use where clause with Truncate
-Truncate faster than both DELETE & DROP
-Rollback is not possible with Truncate

Example 5: mysql on delete set null

FOREIGN KEY (child_col1, child_col2, ... child_col_n)
    REFERENCES parent_table (parent_col1, parent_col2, ... parent_col_n)
    ON DELETE SET NULL
    [ ON UPDATE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } ]

Example 6: delete query

public function deletedata(){	

	$this->db->where('id', 2);	
	$this->db->delete('table_name');

	}